The present invention concerns a filter element for filtering a fluid, in particular a urea solution, as well as a filter device, in particular a urea filter device.
For example, urea solutions are employed in exhaust gas treatment in motor vehicles for reducing nitrogen oxide emissions. In this context, urea solution is injected by nozzles in the exhaust gas manifold. In particular for preventing clogging of the nozzles, the urea solution must be filtered. Often, a filter suitable for filtration of a urea solution is also referred to as urea filter.
For filtering the urea solution it is known to employ a filter element which, at the suction side, is supplied or loaded with vacuum or underpressure. Vacuum causes degassing of the urea solution so that gases will accumulate at the highest region of the filter element or of a filter device receiving the filter element. It is important to guide the accumulated gases in the form of small bubbles out of the filter element or the filter device in order not to impair the function of downstream components, in particular, of the aforementioned nozzles.
A further aspect which is to be taken into consideration when developing filter elements for urea solution is that the urea solutions freeze at approximately −11° C. In this context, it is known for example from WO 2010/139706 A1 to provide a compensation body of elastically deformable material. The compensation body absorbs a volume increase upon freezing of the urea solution.